Under field conditions, plant performance, for example in terms of growth, development, biomass accumulation and seed generation, depends on a plant's tolerance and acclimation ability to numerous environmental conditions, changes and stresses. Since the beginning of agriculture and horticulture, there was a need for improving plant traits in crop cultivation. Breeding strategies foster crop properties to withstand biotic and abiotic stresses, to improve nutrient use efficiency and to alter other intrinsic crop specific yield parameters, i.e. increasing yield by applying technical advances
Plants are sessile organisms and consequently need to cope with various environmental stresses. Biotic stresses such as plant pests and pathogens on the one hand, and abiotic environmental stresses on the other hand are major limiting factors for plant growth and productivity (Boyer, Plant Productivity and Environment, Science 218, 443-448 (1982); Bohnert et al., Adaptations to Environmental Stresses, Plant Cell 7(7), 1099-1111 (1995)), thereby limiting plant cultivation and geographical distribution. Plants exposed to different stresses typically have low yields of plant material, like seeds, fruit or other produces. Crop losses and crop yield losses caused by abiotic and biotic stresses represent a significant economic and political factor and contribute to food shortages, particularly in many underdeveloped countries.
Conventional means for crop and horticultural improvements today utilize selective breeding techniques to identify plants with desirable characteristics. Advances in molecular biology have allowed to modify the germplasm of plants in a specific way.—For example, the modification of a single gene, resulted in several cases in a significant increase in e.g. stress tolerance (Wang et al., 2003) as well as other yield-related traits. There is a need to identify genes which confer resistance to various combinations of stresses or which confer improved yield under suboptimal growth conditions. There is still a need to identify genes which confer the overall capacity to improve yield of plants.
Thus, there is a need to identify genes which confer increased yield of a plant.